My wife has a 2000 Fiesta Finesse 1.3 which i was driving home from work yesterday. It had been raining heavily and I had to go some very deep ford like puddles which stretched accross the road.
I made it through them all and got home without any hiccups. My wife then took the car out and again had to go through some of these ford like puddles. When she got home she said that the temperature light came on shortly whilst she was driving. I Took the car out again to see if it was ok and no lights came on although a large rattle has started when turning the car on and when hitting bumps etc which i hope is just something loosened by the large puddles, maybe the exhaust rattling.. Anyway, that's another issue... I checked the engine bay and all looked fine, didn't appear to be anything out of place so I left it.
I have driven it to work today and noticed that the little red LED to the right of the clock is flashing when accelerating and slowing down. It flashes slowly and builds up to a solid light when accelerating and flashes fast and slows down to a solid light when stopping. It only does this up to about 20 mph and back down again.. Can anyone advise what this means??? I did notice a light flickering on the dash board at one point when I was slowing down but not sure if it was the battery light or the temp light but it never happened again so couldn't confirm..

It may well be that you have got a waterlogged Catalytic converter.
Run the car parked and rev it while someone looks to see if steam or water comes out of the exhaust.
I believe the light increasing with revs and speed may be caused to back pressure in the exhaust.
It may well be worth checking the air filter for water causing under pressure to the engine also.